Former President Jimmy Carter questioned the legitimacy of Donald Trump's presidency on Friday. Mr. Carter said the president would not be in the White House if not for Russian interference in the 2016 presidential election.

"The president himself should condemn it, admit that it happened, which I think 16 intelligence agencies have already agreed to say," Carter said at a panel on human rights hosted by the Carter Center in Leesburg, Virginia.

"There's no doubt that the Russians did interfere in the election, and I think the interference, although not yet quantified, if fully investigated, would show that Trump didn't actually win the election in 2016."

"He lost the election, and he was put into office because the Russians interfered on his behalf," Carter said.

Former President Jimmy Carter: If fully investigated, it would show that Trump didn't actually win the election in 2016. He lost the election and he was put in office because the Russians interfered ...on his behalf.🎥 https://t.co/CYSBIK3qHFpic.twitter.com/o71Z4InVxB

Moderator and historian Jon Meacham then asked the former president if he thinks that Mr. Trump is an "illegitimate president."

"Based on what I just said, which I can't retract," Mr. Carter responded to laughs from the audience. "I would say yes."

Mr. Carter's remarks came just after Mr. Trump met with Russian President Vladimir Putin at the G20 summit in Osaka, Japan. During the meeting, Mr. Trump jokingly told Putin not to "meddle" with the next U.S. election.

After a nearly two-year investigation, special counsel Robert Mueller released his long-awaited report on Russia's efforts to influence the 2016 election in April. Mueller concluded that the president's campaign did not conspire with the Russian government, however, he did not determine whether Mr. Trump committed a crime.

Mr. Trump declared victory shortly after the summary was released, claiming it was a "complete and total exoneration."